1. Field of the Invention
The present invention relates to a technology for verifying the authenticity of a computer program before staring the computer program.
2. Description of the Related Art
Recently, an information processor such as a PC (Personal Computer) has a semiconductor chip (IC) called TPM (Trusted Platform Module) that is a hardware tamper resistant secure chip. The TPM includes a register for storing a hash value and it performs various functions. Those functions include a hash value calculating function for calculating a hash value of a computer program to be started based on a request from, for example, a BIOS (Basic Input/Output System) and storing the hash value in the register, a function for verifying the authenticity of a computer program, and a function of digital signature, electronic authentication and the like. The TPM aims to improve the security of the information processor by using these functions. A conventional technology can be found, for example, in Japanese Patent Application Laid-open No. 2005-227995.
In response to a requirement from market, currently the TPM is installed even in image forming apparatuses, such as copiers, to improve the security thereof. The TPM is advantageous in that it can detect not only an unauthorized tampering with software but also an unauthorized tampering with hardware thereby providing higher security.
Although the TPM offers higher security, it is typically connected to a low-speed bus so that it disadvantageously takes a longer time to calculate a hash value. Because the calculation of the hash value is performed during the information processor's start-up process, there is a problem that the start time is delayed.